Process for textiles with aqueous liquors of polyisocyanates and silica sols

ABSTRACT

An improvement in the process of treating textile materials with aqueous compositions of polyisocyanate materials containing freeisocyanate groups is obtained by incorporating silica sol in the composition. The presence of the silica sol allows the compositions to be applied by the exhaustion method. Optionally, emulsion stabilizer, e.g., polymers of vinyl monomers can be added, as well as electrolytes which speed up drawing onto the textile fibers.

United States Patent Becker et a1.

[54] PROCESS FOR TEXTILES WITH AQUEOUS LIQUORS OF POLYISOCYANATES ANDSILICA SOLS [72] Inventors: Gustav Becker, Leverkusen-Schlebusch; HeinzGriepentrog, Cologne; wolggang Klebert; Friedrich Reich, both ofLeverkusen, all of Germany [73] Assignee: Farbenfabriken BayerAktiengesellschaft,

Leverkusen, Germany [22] Filed: Mar. 27, 1969 [21] Appl. No.: 811,258

[30] Foreign Application Priority Data Apr. 6, 1968 Germany ..P 17 69121.3

[52] US. Cl ..117/161 ZB, l l7/l38.8 R, 1 l7/138.8 F, ll7/l38.8 D,ll7/l38.8 E, 1l7/l38.8 N, ll7/139.5 A, 117/141, 117/161 KP [51] Int. Cl..Cl0m 7/48, D060 29/00 [58] Field ofSearch ..1 17/161 KP, 161 ZB, 139.5A

[56] References Cited UNITED STATES PATENTS 3,351,561 11/1967 Albrechtet al. ..117/100X [15] 3,655,437 [451 Apr. 11, 1972 3,505,252 4/1970Brotherton et a1 ..1 17/161 3,505,262 4/1970 Freyhold et a1 ..1 17/161 X3,243,399 3/1966 Dinges et al. ..1 17/161 X FOREIGN PATENTS ORAPPLICATIONS 745,960 3/1956 Great Britain ..1 17/161 OTHER PUBLICATIONSLiquid Castable Elastomers from l-Iydroyxl-Terminated Polybutadienes byVerdol et al. in 2 parts part I Rubber Age July 1966 pp. 57- 64 part 11Rubber Age August 1966 pp. 62- 68 Primary Examiner-William D. MartinAssistant ExaminerMathew R. P. Perrone Attorney-Plumley, Tyner & Sandt[57] ABSTRACT 5 Claims, No Drawings PROCESS FOR TEXTILES WITH AQUEOUSLIQUORS OF POLYISOCYANATES AND SILICA SOLS The present invention relatesto a process for the finishing of textile materials; more particularlyit concerns a process wherein the textile materials are treated withaqueous liquors which contain isocyanate group-carrying reactionproducts of compounds of molecular weight 500 to 6,000 containing atleast two hydroxyl groups, with polyisocyanates; the process ischaracterized in that the textile materials are treated according to theexhaust process with aqueous liquors which contain silica sols, inaddition to the isocyanate group-containing reaction products.

The silica sols to be used in the process according to the invention arecommercial silica sols the particle size of which is comprised, forexample, between and 50 m The amount in which the silica sols are addedto the aqueous liquors may vary within wide limits; in general, anaddition of 0.3-5 g per liter of treating liquor has proved to beadvantageous.

The isocyanate group-containing reaction products used in the aqueousliquors are obtained in known manner by reacting the compounds ofmolecular weight 500 to 6,000 which contain at least two hydroxylgroups, with a stoichiometric excess, calculated on the hydroxylcontent, of polyisocyanates or their bisulphite addition products atelevated temperatures.

Examples of compounds of molecular weight 500 to 6,000 which contain atleast two hydroxyl groups are polyalkylene ether glycols, such aspolyethylene, polypropylene, polybutylene or polyhexylene glycol;polyalkylene ether polyols, e.g., polyalkylene ether triols, such as theaddition products of ethylene and propylene oxide on totrimethylolpropane; furthermore polyesters, as are obtained, forexample, from aliphatic dicarboxylic acids, such as succinic acid,adipic acid, sebacic acid or maleic acid, and polyhydric alcohols, suchas ethylene glycol, diethylene glycol, propylene glycol, butanediol andneopentyl glycol.

Examples of polyisocyanates are aliphatic diisocyanates, such astetramethylene diisocyanate, hexamethylene diisocyanate, l,4-cyclohexanediisocyanate, 4,4 -dicyclohexylmefitane diisocyanate, and 2,4- and2,6-hexahydrotoluylene diisocyanate; diisocyanates, such as p-phenylenediisocyanate and 2,4- or 2,6-toluylene diisocyanate; as well astriisocyanates, such as the reaction product of the formula OCN-(CHN[CONI-l-(CH NCO] which can be obtained from 3 mol hexamethylenediisocyanate and 1 mol of water.

The content of isocyanate group-containing reaction products in theaqueous liquors may vary within wide limits; in general, amounts of 0.2to 20 g, preferably 0.5 to 5 g, per liter of liquor have provedsatisfactory.

In order to stabilize the liquors which contain isocyanategroup-carrying reaction products, it is expedient to add emulsionstabilizers to the liquors. Emulsion stabilizers are, for example,anion-active compounds, such as fatty alcohol sulphates or paraffinsulphonates, and, in particular, non-ionic compounds, such as thepolymers or copolymers prepared from vinyl or divinyl monomers.

The polymers and copolymers used as emulsion stabilizers in the aqueousliquors may be based on the following vinyl or divinyl monomers, forexample: ethylene, propylene, vinyl chloride, vinyl acetate, vinylethers, such as vinyl ethyl ether; furthermore, styrene ordivinyl-benzene, butadiene, isoprene or chloroprene; and -unsaturatedcarboxylic acids, such as acrylic acid and methacrylic acid as well astheir nitriles, esters and amides. Polymers which contain groups capableof reacting with isocyanates have proved particularly advantageous; forexample, the polymers or copolymers prepared from acrylic acid,methacrylic acid, their hydroxyalkyl esters or amides; as well as thecopolymers which are obtained when N- methylol-acrylamide,N-methylol-methacrylamide, or their derivatives prepared by the reactionwith alcohols containing at least one further functional group, arecopolymerised with other olefinic-unsaturatcd compounds, for example,according to the process of U.S, Pat. No. 3,243,399 British Pat. No.1,002,451).

The amounts in which the emulsion stabilizers are added to the aqueousliquors may vary within wide limits; however, it has proved particularlyadvantageous, for example, to add fatty alcohol sulphates or paraffinsulphonates in an amount of 0.01 to 2 g, preferably 0.05 to 0.2 g, perliter of liquor, and the polymers or copolymers in an amount of 0.] to20 g, preferably 1 to 3 g, per liter of liquor.

In order to reduce the period of time during which the polymers andisocyanate group-containing reaction products draw on the textilematerials, it is frequently advisable to add electrolytes to thetreating baths, for example, alkali metal and ammonium salts ofinorganic acids, e.g., sodium sulphate, ammonium phosphate, or alkalimetal and ammonium salts of organic acids, e.g., sodium acetate andammonium acetate. The amounts in which the electrolytes are added to theliquors may vary within wide limits; in general, amounts of 2 to 10 gper liter of liquor have proved satisfactory.

The treatment of the textile materials according to the process of theinvention can be carried out, for example, by agitating the textilematerials at room temperature in a liquor ratio of l 6 to l 50 in theaqueous liquor which contains the isocyanate group-carrying reactionproducts and optionally contains emulsion stabilizers and the pH valueof which amounts to about 4-6, for a short time, about I to 20 minutes;then adding the silica sol; again allowing the liquor to act for a shorttime, about 5 to 30 minutes; then, optionally after the addition of anelectrolyte and another brief action of the liquor for about 5 to 30minutes, centrifuging or squeezing; and subsequently drying.

The textile materials treated in this way, such as yarns, texturedyarns, fabrics, knitted fabrics or finished articles of fabrics andknitted fabrics, may subsequently be subjected to other finishingprocesses, e.g., dyeing, optionally after an ageing treatment with H Oor after a short storage for about 1 to 2 days.

With the aid of the process according to the invention it is possible toimpart an excellent finish to textile materials of natural polyamides,such as wool and silk, caseine fibres, or synthetic fibers, such aspolyamide, polyurethane, polyester, polycarbonate, polyacrylonitrile,polypropylene fibres. The treated textile materials are characterized byexcellent properties in use, such as resistance to scraping, creasing,and pilling and by insensitivity to soiling. In textile materials ofwool, moreover, an excellent felt-free finish is achieved, which is fastto washing. The feel of the textile materials can also be advantageouslyaffected by the process according to the invent1on.

The parts given in the examples are parts by weight.

EXAMPLE 1 A pre-washed worsted fabric of pure wool is treated in awashing machine in a liquor ratio of l 5 at room temperature for about10 minutes with an aqueous liquor containing, per liter,

60 g of a mixture prepared by stirring into 12 g of the 50 percent stockemulsion described below first 3 g of the 40% aqueous copolymerdispersion described below, and then 45 ml of water.

Before adding the mixture, the pH value of the liquor had been adjustedto 4.5-5 by the addition of acetic acid. There is then added to theliquor, per liter,

2 g of 30 percent silica sol,

diluted with 18 ml of water and acidified to pH 5-6 with acetic acid,and the treatment is continued for another 30-40 minutes. Subsequentlythere is added to the liquor, per liter,

6 g of sodium acetate,

dissolved in 40 ml of water, and the treatment is again continued for10l5 minutes. The worsted fabric is then centrifuged and dried on astenter at C. By the treatment there is obtained an excellent feltfreefinish which is fast to washing and a very good creasing resistance ofthe worsted fabric.

The 50 percent stock emulsion used above was obtained in the followingway:

1,000 parts of an 80 percent solution of the isocyanate group-containingreaction product described below, in ethyl acetate were slowly poured,while vigorously stirring with a high capacity rapid stirrer(3,000-l0,000 r.p.m.) into 980 parts of cold water which had beenacidified to pH 5-6 with acetic acid and mixed with 20 g paraffinsulphonate. The emulsion was ready after stirring for 3 to 5 minutes.

The reaction product containing isocyanate groups was obtained in thefollowing way:

3,000 parts of a polypropylene glycol having a molecular weight of about2000, a OH number of 55.5 and an acid number 0.5 were heated with 535parts hexamethylene diisocyanate at 110 C. for 2 hours and subsequentlyat 130-l40 C for 1% hours.

The 40 percent aqueous copolymer dispersions was obtained bycopolymerization of 60 parts acrylic acid butyl ester, 30 parts styreneand parts acrylic acid amide in water.

EXAMPLE 2 A loose wool fabric is treated in a nozzle washing machine,after washing and without intermediate drying, in a liquor ratio of l 6at room temperature for about 2 minutes with an aqueous liquorcontaining, per liter,

27.5 g ofa mixture prepared by stirring into 6 g of the 50 percent stockemulsion described below first 1.5 g of the 40 percent aqueous copolymerdispersion described in Example 1 and then 20 ml of water.

Before adding the mixture, the pH value of the liquor had been adjustedto pH 45-55 by the addition of acetic acid. There is then added to theliquor, per liter,

1.5 g of 30 percent silica sol diluted with 13 ml of water and acidifiedwith acetic acid to pH 5-6, and the treatment is continued for another15-20 minutes. Subsequently, there is added to the liquor, per liter,

4.5 g of sodium acetate,

dissolved in 15 ml of water, and the treatment is again continued for5-10 minutes. The wool fabric is then centrifuged and dried on a stenterat 90-1 lObL C. The treated wool fabric is characterized by a fullhandle and excellent felt-free effects, besides very good properties inuse, such as resistance to scraping, creasing and pilling.

The 50 percent stock emulsion was prepared as described in Example 1,but the isocyanate group-containing reaction product there used wasreplaced with the reaction product obtained in the following way:

1,000 parts of a branched polypropylene glycol which had been preparedby propoxylation of trimethylolpropane and had a molecular weight of3,750, a OH number of and an acid number 0.5 was heated with 135 partshexamethylene diisocyanate at 110 C for 2 hours and subsequently at 130C for 1 hour.

EXAMPLE 3 A costume fabric of pure wool (pique) is treated in a nozzlewashing machine operating at low gear, in a liquor ratio of 1 6 at roomtemperature for about 10 minutes with an aqueous liquor containing, perliter,

52.2 g of a mixture prepared by stirring into 10 g of the percent stockemulsion described in Example 1 first 2.2 g of the 40 percent copolymerdispersion described in Example 1 and then 40 ml of water.

Before adding the mixture, the pH value of the liquor had been adjustedto 4.5-5 by the addition of acetic acid. There is then added to theliquor, per liter,

1.5 g of 30 percent silica sol diluted with 12 ml of water and acidifiedto pH 5 with acetic acid and the treatment is continued for another 20minutes. Subsequently, there is added to the liquor, per liter,

4.5 g of sodium acetate dissolved in 15 ml of water and the treatment iscontinued for another 25 minutes. The wool fabric is then centrifugedand dried at 100 C. There is obtained a wool fabric with an excellentshrink-proof finish and very good properties in use, such as resistanceto scraping and creasing.

EXAMPLE 4 Pullovers of carded yarn (Shetland wool) are treated in a drumwashing machine in a liquor ratio of 1 10 at room temperature for about5-10 minutes with an aqueous liquor containing, per liter,

52 g of a mixture prepared by stirring into 10 g of the 50 percent stockemulsion described in Example 2 first 2 g of the 40 percent copolymerdispersion described in Example l and then 40 ml of water. Before addingthe mixture, the pH value had been adjusted to 45-5 by the addition ofacetic acid. There is then added to the liquor, per liter,

1 g of 30 percent silica sol diluted with 10 ml of water and acidifiedto pH 5-6 with acetic acid and the treatment is continued for another 20minutes. Subsequently, the pullovers are centrifuged and dried in atumbler at -90 C. An excellent felt-free finish of the pullovers, whichis fast to washing, is achieved by the treatment. Moreover, the knittedfabric has a very good resistance to scraping and pilling.

EXAMPLE 5 Lambswool pullovers in the grey are treated in a paddlemachine in a liquor ratio of l 30 at room temperature for about 10minutes with an aqueous liquor containing, per liter,

26 g of a mixture prepared by stirring into 5 g of the 50 percent stockemulsion described in Example 1 first l g of the 40 percent copolymerdispersion described in Example l and then 20 ml of water. Before addingthe mixture, the pH value of the liquor had been adjusted to 4.5-5 bythe addition of acetic acid. There is then added to the liquor, perliter,

0.5 g of 30 percent silica sol diluted with 5 ml of water and acidifiedto pH 5-6 with acetic acid and the treatment is continued for another 20minutes. The pullovers are subsequently dyed by the methodconventionally used for knitted articles of wool at boiling temperaturefrom a long bath. After rinsing, centrifuging and drying, the pulloversare shaped and steamed. The pullovers thus treated are characterized bya soft flowing handle and by good resistance to pilling and they have anexcellent felt-free finish.

EXAMPLE 6 Pullovers of pure wool in the grey are treated in a washingmachine in a liquor ratio of l 10 at room temperature for about 10minutes with an aqueous liquor containing, per liter,

38 g of a mixture prepared by stirring 30 ml of water into 8 g of the 50percent stock emulsion described in Example Before adding the mixture,the pH value of the liquor had been adjusted to 4.5-5 by the addition ofacetic acid. There is then added to the liquor, per liter,

2 g of 15 percent silica sol diluted with 20 ml of water and acidifiedto pH 5-6 with acetic acid and the treatment is continued for anotherl5-20 minutes. Subsequently, there is added to the liquor, per liter,

3 g of sodium acetate,

Anna.

dissolved in 15 ml of water and the treatment is again continued for -15minutes. After centrifuging and drying in a tumbler, the pullovers aredyed by the method conventionally used for knitted articles of wool froma long bath. After another centrifuging and drying at 80-90 C, thepullovers are shaped and steamed. The treated pullovers arecharacterized by a pleasant handle and very good pilling resistance andthey have an excellent felt-free finish.

EXAMPLE 7 Stockings of pure wool are treated in a drum washing machinein a liquor ratio of l 1 10 at room temperature for about 10 minuteswith an aqueous liquor containing per liter,

32.5 g ofa mixture prepared by stirring into 6 g of the 50 percent stockemulsion described in Example 1 first 1.5 g of the copolymer dispersiondescribed in Example 1 and then 25 ml ofwater. Before adding themixture, the pH value had been adjusted to 4.5-5 by the addition ofacetic acid. There is then added to the liquor, per liter,

1 g of percent silica sol diluted with 10 ml of water and acidified topH 5-6 with acetic acid. The treatment is continued for another 15-20minutes. Subsequently, there is added to the liquor, per liter,

3 g of sodium acetate dissolved in ml of water and the treatment isagain continued for 15-20 minutes. The stockings are then centrifuged,dried in a tumbler at 8090 C and subjected to the usual shaping andsteaming processes. The stockings thus treated are characterized byoutstanding resistance to shrinkage, very good pilling resistance andfastness to scraping.

EXAMPLE 8 A mixed fabric consisting of 55 percent of polyacrylonitrilefibre and 45 percent of wool is treated in a noule washing machine in aliquor ratio of 1 6 at room temperature for about 10 minutes with anaqueous liquor containing, per liter,

46 g ofa mixture prepared by stirring into 9 g of the 50 percent stockemulsion described in Example 2 first 2 g of the 40 percent copolymerdispersion described in Example l and then 35 ml of water. Before addingthe mixture, the pH value of the liquor had been adjusted to 4.5-5 bythe addition of acetic acid. There is then added to the liquor, perliter,

1.5 g of 30 percent silica sol diluted with 12 ml of water and acidifiedto pH 5-6 with acetic acid and the treatment is continued for another30-40 minutes. Subsequently, there is added to the liquor, per liter,

4.5 g of sodium acetate dissolved in 15 ml of water and the treatment isagain continued for 10-15 minutes. The fabric is then calendered in acontinuous calender, subsequently centrifuged and dried on a stenter.The treated fabric is characterized by a full firm handle, very goodpilling resistance, fastness to creasing and scraping. It is alsodirtrepellent.

EXAMPLE 9 A mixed fabric consisting of 55 percent of polyester fibre and45 percent of wool is treated in a winch vat in a liquor ratio of l 40at room temperature with an aqueous liquor containing, per liter,

12.5 g ofa mixture prepared by stirring into 2 g of the 50 percent stockemulsion described in Example 1 first 0.5 g of the 40 percent copolymerdispersion described in Example 1 and then 10 ml of water.

Before adding the mixture, the pH value of the liquor had been adjustedto 4.5-5 by the addition of acetic acid. There is then added to theliquor, per liter,

0.4 g of 30 percent silica sol diluted with 4 ml of water and acidifiedto pH 5-6 with acetic acid and the treatment is continued for another30-40 minutes. Subsequently, there is added to the liquor, per liter,

1 g of sodium acetate dissolved in 5 ml of water and the treatment isagain continued for 10-15 minutes. The fabric is then calendered in acontinuous calender, subsequently centrifuged and dried on a stenter.The fabric is then therrnofixed at l85 C for about 30 seconds andfinished in the usual way. The treated fabric is characterized by apleasant full handle, good fastness to wet creasing and good pillingresistance. The wool component also has an excellent felt-free finish.

A fabric with a similar good finish is obtained when the mixed fabric isfirst therrnofixed and then subjected to the treatment with the aqueoustreatment liquor described above.

EXAMPLE 10 Woollen yarn in hanks is treated, after dyeing and rinsingbut without intermediate drying, in a liquor ratio of l 40 in a dyeingapparatus for about 10-15 minutes with an aqueous liquor containing, perliter,

10 g of a mixture prepared by stirring into 2 g of the 50 percent stockemulsion described in Example 2 first 0.5 g of the 40% copolymerdispersion described in Example 1 and then 7.5 ml of water.

Before adding the mixture, the pH value of the liquor had been adjustedto 4-4.5 by the addition of acetic acid. There is then added to theliquor, per liter,

0.4 g of 30 percent silica sol diluted with 4 ml of water and acidifiedto pH 5-6 with acetic acid and the treatment is continued for anotherl5-20 minutes. Subsequently, there is added to the liquor, per liter,

1 g of sodium acetate dissolved in 5 ml of water and the treatment isagain continued for 10 minutes. The yarn hanks are then centrifuged anddried. The knitted fabrics produced after l-2 days storage from the yarnthus treated have an excellent felt-free finish and are characterized bygood resistance to scraping, wet creasing and pilling.

EXAMPLE ll Undyed wool yarn is treated in a dyeing apparatus in a liquorratio of l 40 at room temperature for about 10-15 minutes with anaqueous liquor which contains, per liter,

3 g of the 50 percent stock emulsion described in Example 1 and 0.1 g ofan approximately 30 percent aqueous solution of a fatty alcohol sulphateand the pH of which has been adjusted to 4.5-5 by the addition of aceticacid. There is then added to the liquor, per liter,

0.4 g of 30 percent silica sol diluted with 4 ml of water and acidifiedto pH 5-6 with acetic acid and the treatment is continued for another15-20 minutes. Subsequently, there is added to the liquor, per liter,

1 g of sodium acetate dissolved in 5 ml of water which has beenacidified to pH 5-6 with acetic acid and the treatment is againcontinued for about 10 minutes. After the addition of 0.5 g sodiumpyrophosphate and 5 g of 35 percent hydrogen peroxide per liter ofliquor, the treating bath is heated to 50 C within 1 hour and kept atthis temperature for 30 minutes. After draining off the liquor andrinsing, the yarn is dyed in the usual manner from a weakly acidic bath.The knitted fabrics produced from the yarn have an excellent felt-freefinish and a full woolly handle, and they are characterized by goodresistance to scraping, pilling and wet creasing.

EXAMPLE 12 A knitted fabric of a textured polyamide fiber is treated ina winch vat in a liquor ratio of l 40 at room temperature for about 15minutes with an aqueous liquor which contains, per liter,

1.5 g of the 50 percent stock emulsion described in Example 1 and 0.25 gof a 30 percent fatty alcohol sulphate solution and the pH value ofwhich has been adjusted to 4.55 by the addition of acetic acid. There isthen added to the liquor, per liter,

0.25 g of 30 percent silica sol diluted with 2.5 ml of water andacidified to pH 5-6 with acetic acid and the treatment is continued foranother minutes. Subsequently, there is added to the liquor, per litre,

l g of sodium acetate dissolved in 5 ml of water which has beenacidified to pH 5-6 with acetic acid and the treatment is continued fora further 20 minutes while the bath temperature is raised to 45 C. Theknitted fabric is subsequently rinsed, centrifuged and dried. When dyedafter 12 hours storage, the treated knitted fabric is characterized inthat it does not exhibit the inconvenient wet stiffness. Furthermore,the finished knitted fabric has a pleasant handle which is fast towashing and dry cleaning, an excellent retention of shape and fastnessto creasing.

We claim:

1. In the process for finishing textile material by treating withaqueous liquors comprising isocyanate group-containing reaction productsof (A) stoichiometric excess of organic polyisocyanates with (B)compounds having a molecular weight of 500-6,000 and containing at least2 hydroxyl groups; the improvement which comprises applying said aqueousliquor containing 0.3 to 5 g per liter of silica sol as an additionalingredient, by exhaustion onto said textile material.

2. The process of claim 1 wherein the aqueous liquor contains, inaddition, an emulsion stabilizer.

3. The process of claim 2 wherein the emulsion stabilizers are polymersor copolymers prepared from vinyl or divinyl monomers.

4. The process of claim 2 wherein the aqueous liquor contains, inaddition, an electrolyte.

5. The process of claim 1 wherein the ratio of textile material toliquor is 1:6 to 1:50.

UNTTTD STATES PATENT OFFICE QETRHHCATE OF QGRREGHON Data; April 11.,1972 It is certified that error appears in the above-identified patentand that said Letters Patent are hereby corrected as shown below:

Error "50m. should read SOm u.

"4,4" should read 4 ,4

"; diisocyanates" should read z aromatic diisocyanates mew (on) -N-=[comw (cm-moo] should OCN- (CH N- [CON'H- (CH -NCO] 2 "and, should readand i, fi

"'HO should read H 0 "llGbLC" should read 110C sealed this 22nd day ofJanuary l97i RENE Do TEGTMEYER Acting Commissioner of Patents Patent No.a

Inventor(s) BECKER ET ALO COlIlIIlIflZ Line l formula Signed and (SEAL)Attest:

EDWARD MQFLETCHELmJR. Attesting Officer FORM PO-105O (10-59) USCOMM-DC60376-P6Q u.s. covannmzm HUNTING orrgcs: was o-aes-szqa

2. The process of claim 1 wherein the aqueous liquor contains, in addition, an emulsion stabilizer.
 3. The process of claim 2 wherein the emulsion stabilizers are polymers or copolymers prepared from vinyl or divinyl monomers.
 4. The process of claim 2 wherein the aqueous liquor contains, in addition, an electrolyte.
 5. The process of claim 1 wherein the ratio of textile material to liquor is 1:6 to 1:50. 